This invention relates to the body of a front loading refuse truck, i.e., a front loader. More particularly, this invention relates to a front loader body that has fewer parts, requires fewer welds during assembly and is therefore easier to manufacture and is less costly. Even more particularly, this invention relates to the shape and orientation of the sidewalls of the front loader body which ensure that the sidewalls will not interfere with the operation of the loading arms and which results in a front loader that is strong yet lightweight.
Front loaders are well-known conventional refuse equipment. In a front loader, refuse from garbage containers is deposited into the front loader body for compaction and transportation to a dump site. The refuse is deposited into the hopper portion of the front loader, which is the front portion of the body, via an opening in the top of the front portion of the body. Mechanical loading arms are pivotally attached on either side of the body near the front of the unit. Forks on the forward end of the loading arms engage the garbage containers and the loading arms pivot about their point of attachment In this manner, the loading arms position the garbage containers over the opening and the forks rotate to tip the garbage containers to discharge the refuse into the front loader. After the refuse has been emptied from the garbage containers, the forks rotate the containers to an upright position and then the loading arms swing down and place the garbage containers back on the ground. After the refuse is deposited into the hopper, a packer panel packs the refuse into the storage area of the front loader body, which is the rear section of the front loader.
This loading and packing process is repeated at various points along a garbage collection route. As more and more refuse is loaded and packed into the storage area, the refuse exerts pressure against the floor, roof and sidewalls of the front loader body. When the body is completely filled with refuse, the front loader travels to a dump site to empty the refuse from the body.
ln order to operate most efficiently, the front loader should be able to pack a large quantity of refuse into its body. In this way, the front loader will spend more time collecting refuse along a collection route and will spend a minimal amount of time traveling to and from a dump site.
State and federal laws strictly limit the height, length and width of all trucks. These limitations also apply to front loaders. The length of a front loader is also limited by the practical problem of maneuverability on city streets and alleys. Thus the maximum dimensions of the front loader are determined. A more efficient front loader will be able to pack large quantities of refuse into the defined volume of the front loader body. Therefore, the front loader body must be strong in order to withstand the high pressures exerted on it by the large quantities of refuse that must be packed into the front loader.
State and federal laws also strictly limit the weight of all trucks. Therefore, the total weight of a front loader packed with refuse must not exceed a certain maximum legal limit. An efficient front loader will have a body that is both strong and lightweight.
One means of decreasing the weight of the body is to make the body out of a strong and light material such as an aluminum alloy. Such an aluminum alloy is 6061-T6 or 5454-H32, which are standard, commercially available alloys. However, the use of an aluminum alloy in present front loader body designs is not entirely satisfactory.
In order to withstand the high pressures generated inside the front loader body, a plurality of braces are typically disposed along the roof, floor and sidewalls of the front loader body. These braces are welded onto the body. Unfortunately, the heat generated in the welding process adversely affects the strength of the aluminum alloy. Excessive welding along the surface of an aluminum alloy will drastically reduce the strength of the alloy. The weakened alloy will be unable to withstand the pressure inside the front loader body making the alloy unfit for use in a front loader.
The addition of braces to the roof, floor and sidewalls of a front loader to increase strength will also increase the front loader's weight. This added weight limits the weight, and therefore the volume, of refuse that legally can be carried in the unit. As a result, the heavier front loader will reach the weight limitation sooner than a lighter front loader and must travel to and from a dump site more frequently than a lighter front loader.
One well-known means of increasing the strength of the roof, floor and sidewalls of a front loader without the use of braces is to make these surfaces curved. The use of curved surfaces for a container to impart strength to the container without the addition of races to these surfaces is conventional. For example, U.S. Pat. Nos. 3,339,499; 3,490,387; 3,427,994 and 3,495,548 all disclose railroad hopper cars having curved sidewalls and a curved roof.
However, merely using a curved surface is not entirely satisfactory for the hopper section of a front loader. To withstand the pressure imposed by the refuse, the surfaces of the body should be curved to a high degree, i.e., these surfaces should have a small radius of curvature. If a surface having a high degree of curvature is used for the sidewalls in the hopper section of the front loader and these sidewalls are spaced to maintain an adequate hopper opening, the sidewalls will interfere with the free rotation of conventional loading arms. Also, if a surface having a high degree of curvature is used for the sidewalls in the hopper section of the front loader and the sidewalls are spaced to maintain adequate loading arm clearance, the sidewalls will create a narrow hopper opening. This narrow opening will not allow garbage containers having standard opening to be freely dumped into the front loader. Moreover, if the degree of curvature is too small, without additional bracing, the sidewalls will be unable to withstand the internal pressure caused by the packed refuse and will fail.